Listed in the data table are IQ scores for a random sample of subjects with medium lead levels in their blood. Also listed are statistics from a study done of IQ scores for a random sample of subjects with high lead levels. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Complete parts (a) and (b) below. E Click the icon to view the data table of IQ scores. .... a. Use a 0.01 significance level to test the claim that the mean IQ scores for subjects with medium lead levels is higher than the mean for subjects with high lead levels. What are the null and alternative hypotheses? Assume that population 1 consists of subjects with medium lead levels and population 2 consists of subjects with high lead levels. VB. Ho P = P2 OA. Họ P1 = P2 OC. Ho H1 H2 H 2 OD. Ho H1 SP2 H P2 The test statistic is. (Round to two decimal places as needed.)

Estimated Speed   Smashed into hit n = 16 n = 16 M = 40 M = 34 SS = 510 SS = 414  Use a one-tailed test with α = .01.  The t-statistic is

Test the claim that for the population of statistics final exams, the mean score is 7676 using alternative hypothesis that the mean score is different from 76.76. Sample statistics include ?=21,n=21, ?⎯⎯⎯=78,x¯=78, and ?=11.s=11. Use a significance level of ?=0.05.α=0.05. (Assume normally distributed population.) The test statistic is The positive critical value is The negative critical value is The conclusion is A. There is sufficient evidence to reject the claim that the mean score is equal to 76. B. There is not sufficient evidence to reject the claim that the mean score is equal to 76.

Test a claim that the mean amount of lead in the air in U.S. cities is less than 0.036 microgram per cubic meter. It was found that the mean amount of lead in the air for the random sample o 57 U.S. cities is 0.039 microgram per cubic meter and the standard deviation is 0.069 microgram per cubic meter. At α=0.10​, can the claim be​ supported? Complete parts​ (a) through​ (e) below. Assume the population is normally distributed.

Impact of the Population Standard Deviation on SE Compute the standard error for sample means from populations all with mean μ = 80 and with standard deviations o and o = 75 using a sample size of n = 90. Round your answers to two decimal places, if necessary. Standard Deviation o = 11: o = 40: o = 75: HI Standard Error = 11, o = 40,

Test the claim that the mean GPA of night students is significantly different than 2.8 at the 0.1 significance level.   Based on a sample of 70 people, the sample mean GPA was 2.81 with a standard deviation of 0.03   The positive critical value is: (to 2 decimals)

78   Answer was incorrect

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Using Symmetry and the Empirical Rule A standardized test is approximately normally distributed with a mean score of 7272 and a standard deviation of 55. Use the symmetry of the normal curve and apply the Empirical rule to answer the questions. Make a sketch of the curve to help you determine the areas.Note: You must use the Empirical Rule values 68%68%, 95%95%, and 99.7%99.7% in your computations. The computer calculator will not give you the correct answer. What percent of students scored greater than 7272?____ % What percent of students scored between 7272 and 7777?_______ % What percent of students scored between 6767 and 7777? ______% What percent of students scored between 5757 and 6262? _____%

n=10, x=10.3, s=4.4, 95% confidence use the given degree of confidence and sample data to construct a confidence interval for the population mean u. assume that the population has a normal distribution